WASHINGTON — The sanctions imposed by the Trump administration Thursday include its first use of a new law intended to punish Russia for its interference in the 2016 presidential election campaign.

But a closer look at the list of five entities and 19 individuals added to the sanctions list shows that the move is largely symbolic: About a third had already been sanctioned under the Obama and Trump administrations, and the individual-level sanctions are unlikely to have an effect on the Russian economy.

"Symbolism is important when it comes to sanctions," said Andrew Keller, a former deputy assistant secretary of State for sanctions in the Obama administration. That's particularly true here, he said, because "it’s really the first statement of the Trump administration, from a sanctions standpoint, with regard to Russia's election meddling."

"That said, as a practical matter, these sanctions may not be particularly impactful," he said.

Treasury Secretary Steven Mnuchin said the new round of sanctions shows that the Trump administration is "confronting and countering malign Russian cyber activity, including their attempted interference in U.S. elections, destructive cyber-attacks, and intrusions targeting critical infrastructure."

It's the first round of sanctions under the Countering America's Adversaries Through Sanctions Act — a bill President Trump signed only reluctantly last year in the face of a veto-proof congressional majority. The Treasury Department is using that law to target the Russian Federal Security Service, or FSB; the Main Intelligence Directorate, of GRU; and six GRU officials.

The sanctions freeze any assets of the Russian agents held in U.S. dollars, and block U.S. citizens from engaging in business with them.

Senate Intelligence Committee Vice Chairman Mark Warner said the sanctions were long overdue.

"I think this is a good step. It is not fully sufficient," Warner, D-Va., told MSNBC. "What continues to concern to me is that while you had the administration act, there continues to be a reluctance by the president himself to call out Russia as a bad actor."

Many targets of Thursday's actions were already on U.S. sanctions lists. Yevgeniy Prigozhin, the Russian oligarch known as "Putin's chef," is being sanctioned for the third time after previous designations under the Obama and Trump administrations. Also identified for repeat sanctions: His two companies, Concord Management and Consulting, and Concord Catering.

They join the Internet Research Agency and 12 others indicted by Mueller's grand jury last month. They were all sanctioned under an Obama-era executive order targeting malicious cyber-related activity.

Also cited in the sanctions: the NotPetya cyberattack, which affected hospitals and disrupted shipping last year. In February, the White House attributed that attack to the Russian military, calling it the "most destructive and costly cyberattack in history."

Moscow said Friday it would add more Americans to its "black list" in response to the new sanctions, Russian news agencies reported.

The sanctions had been in the works for weeks, but the timing comes just as the United States condemned Russia for its use of nerve agent to poison a double agent in the United Kingdom, signing on to a joint statement as a sign of solidarity with European allies.

A Treasury Department statement says the nerve agent attack "demonstrates the reckless and irresponsible conduct" of the Russian government. National security officials, speaking on condition of anonymity to discuss internal deliberations, said even more sanctions are in the works.

Sergei Skripal and his daughter, Yulia, were poisoned in the southern English town of Salisbury earlier this month. The attack had all the fingerprints of a Russian spy operation, especially in its use of a military-grade nerve agent developed by Russia and banned by an international treaty on chemical weapons.

In the joint statement with the United Kingdom, France and Germany, the United States closed a gap that had emerged earlier this week when White House appeared to stop short of blaming Russia for the attack.

"We share the U.K. assessment that there is no plausible alternative explanation, and note that Russia´s failure to address the legitimate request by the U.K. government further underlines its responsibility," the four allied countries said in the joint statement. "We call on Russia to address all questions related to the attack in Salisbury."

Speaking to reporters in the Oval Office Thursday, Trump said, "It certainly looks like the Russians were behind it."

It's "something that should never, ever happen, and we’re taking it very seriously, as I think are many others," he said.